Furnace rabble arm



Oct. 16, 1928.

E. J. FOWLER FURNACE RABBLE ARM 3 Sheets-Sheet 2 Filed March 19, 1 927 INVENTOR Zdwa/dJZbwZefi iTTBRNEYS Oct. 16, 1928.

E. J. FOWLER FURNACE RABBLE ARM 5 Sheets-Sheet 3 Filed March 19, 1927 avweuto'c lafiuardlliholer 35% gum/"@130 Patented Oct. 16, 1928.

EDWARD J; rownnn; or mmwoonorry; oatuonmk; martenm mcncns e'oflm COMP-ANY, OFNEW YORK, N: Y.,

aoonp onmon Yon;

FURNACE mines. Arm;

Application filed March19,,1:827 serial in. mm

This invention relates to furnace rabble arn'is as for example rabble arms for multiple hearth rotating shaft furnace constructions;

The objects of this invention include the provision of improved rabble arms, rabble teeth and associated parts of, an inex ensive and durable construction,whichpre erably are made to be readily demountable as for rapid repair and replacement, Furthermore, constructions embodying this invent tion in most instances make possible a substantial saving in. the materials necessary therefor, and also-a saving inthe number of necessary parts. Rabble arms embodying this invention may be readily applied to various existing types-of furnace constructions substantially without alterations to such furnaces.

The invention consists in the novel features, arrangements and combinations of parts embodied by way of eXamplein the apparatus hereinafter described as illustrating a preferred form of the invention, and various. specific objects, features and advantages of the invention will more clearly appear from this description taken in con nection with the accompanying,drawings.

In the drawings, Fig. 1 represents. a verti'al sectional view partly broken away and taken substantially along the vertical axis of a furnace embodying theinvention. I

Fig"; 2 is a top or plan view, partly in section, showing a rabble arm and adaptor member therefor embodying certain features of the invention.

Fig. 3 is an elevational view, partly in vertical section, showing a rabble arm and adai 'itor member embodying features of the invention and attached to a rotatable furnace shaft; 7

4c is a view similar to Fig. 3, but showing a portion of the rabble arm in vertical section and also showing an'adaptor memb r which is ofalength greater than tlie'adaptor member of Fig. 3 for a purpose hereinafter set forth; I

Figs. 5, 6 and 7 respectively are transverse sectional views of the rabble arm and "daptor members taken substantially along the section lines 5, 6 and 7 of Fig. 3; I

Fig. 8 is a longitudinal sectional View;

taken substantially along the line 8 8 of Fig.8;

t thon the several arms,

Figs. and. 10 respectively are top s de y ewsflshowing a rabble {00th mnbodymg. features ofithe invention; and y Figs. 1 1.16'linclusive are, longitudinal and transverse" sectional. views showing the in? ventio'n in certain-eras. phases for applicaii'i the usual manner as .by a substantially cylindrical furnace wall 25.. A' rotatable and internall cool'edpentral shaft 26 extends vertical up through the furnace substantially along the central axis thereof, for

supporting a number of rabble arms extendi'ngradia ly from th'e'shait into the spaces betweensucceeding hearths. Rabble teeth are provided on each of therabble' arms for stirring and advancing the material being treated successivelyover each of tliehearths.

The common practice hasbeen top'rovide a series o'f' rabble' teeth on each arm, the arm being formed with a suitable; longitudinal slot for. receiving the numerous rabble teeth accompanied by spacer members. By the use" spacer members, the teeth. are spaced along the length of the am so that over each hearth the respective paths of travel of the teeth on the several arms for that heartli will be irrterspacd, thus g'i'ving a uniform rabbling action over thearea of the hearth; However, with such construction, inorder to replace broken or worn out teeth,

it is-sometimes necessar to. first successively remove each of a long se ri es'of teeth and spacer members before the broken tooth can be reached; since the teeth are all arranged in succession within a single slot extending the length of the arm; Therenitival of such an a r-mas zrwh o le with the teeth attached is difficult alternative'; because of the length'of'the arm and its'great weight when equipped with" the numerous teeth" and spacer; member Eur-the m re, in setting u furnaces of the conventional ty es, hferee I teferused; separate attention must begi'vn to the roper; positioning of] each of the n mero s teeth in rder to a.tai.iithe desired interspacing of the paths 0 travel 01 the The construction about to be described substantially eliminates these difficulties and also embodies additional advantages.

The invention herein relates more particularly to certain novel features of construction embodied inthe rabble arms and associated parts and accordingly, as to the design and constructional details of other parts of the furnace not specifically referred to herein, the usual practice maybe followed as carried out in the construction of other well known furnaces of this general type.

As indicated in Figs. 2-8 inclusive, a rabble armis provided having two substantially concentric tubular members 7 and 28, the outer member 27 forming asupport or body memberfor carrying the rabble teeth and the inner member 28 comprising a conduit for controlling the circulation of cooling fluid within the arm. It will be noted that the outer member has a cross-section substantially larger than the inner member and that the two members are thus spaced apart bv an annular passageway 29, which receives the circulating cooling fluid. The tubular member 27 may be provided at 30 with a relatively narrow bearing area which encircles the member. and isdesigned to be fitted into a corresponding bearing portion formed upon a furnace rabble arm adaptor member 31, (or3l as shown in Fi 4), as hereinafter described. Beyond said bearing area the tubular member 27'is extended and formed ith a relatively restricted or substantially conical end portion 32,- which is tapered down to such a diameter that its peripheral ed es at 33 closely embrace and may be joined to the corresponding peripheral edges at the inner end of the. conduit 28 (see Figs. 5t and 8). The innerend of the conduit is thereby securely held in position with its walls substantiallyconcentric with the outer tubular member. Except for the inner end out the conduit 28, its walls are thus substantially spaced from the body member of the rabble arm and accordingly uniform heat radiation and cooling of the inside walls of the rabble arm are not interierredwthby the bearing parts nor by the presence of the conduit. It will be noted that the conduit joins the outer tubular member at a point whollywithin the limits of the walls of theadaptormember and accordingly the joint is protected from the high temperatures prevailing within the furnace. The restricted or conical portion 32 may be formed with suitable large perforations or openings as at 34 and 35 which provide' passages permitting the cooling fluid to freely circulate from the annular passage 29 out of the rabble arm and into the passages of the adaptor member as. hereinafter described. At the'same time suificient wall area remains in the conical portion 32 to provide ample strength. i

The adaptor members 31 or 31 may comprise an outer approximately cylindrical body member 36 formed at one end with a suitable flanged means 37 designed tobe bolted as by bolts 38 in a conventional manner to a corresponding flanged portion 39, as provided upon the central rotatable shafts of many roasting furnaces of this general type now in use. At its outer end the adaptor member is formed with an annularbearing portion 40. for receiving the bearing area 30 above described. The rabble arm may be secured in position with the bearing portions 30 and 40 in engagement by means of a pin member 41 fitting into suitable algned apertures extending through the two b earingfportions. It will be noted that with the rabble arm in position the'wall's of the adaptor member are substantially spaced from the end portion of the rabble arm except at the narrow bearing area 40. The

hollow adaptor member being filled With the circulating cooling fluid, a uniformcoolinc action over all of the portions of the join" area is insured. The walls of the adaptor member and of the rabble arm are preferably substantially free from reinforcing ribs, thickened areas, etc, which further contrib utes to the same result. The elimination of reinforcing ribs and the like not only results in a saving of material and reduction ct weight, but also prevents.non-uniform temperature conditions and the consequent destructive forces and strains which tend to arise within thick metal parts.

Within the adaptor member a cooling fluid conduit portion 42 may be formed, either integrally with the outer adaptor housing or as a separate part fitting therein. The central shaft of the furnace may be formed in sections as ofcast iron and inside of each section and preferably concentric with the outer walls 43 a cooling fluid conduit as i at i l is provided. At'each point-where rabblearms are to be attached the shaft sections are provided with one of the bearing areas 39. Also opposite each rabble arm the conduit i4 is provided with a branch extension 45 having openings within the-limits of the bearing areas 89. The outer space within theadaptor member is designed to be communicative with the s pace between the shatt wall 43 andthe conduit let, whereas,

the conduit portion 42 within the adaptor isportion 4-2 and the rabblearm conduit2S.

Vith this construction two widely spaced bearmgs at $0 and 46. are provided. for the lit) nemesis thorough cooling of the interior surfaces of the adaptor member andrabble arms. At

7 the same time this construction providesa durable interengaging plug and socket means between the adaptor and arm, whereby the armis readil demountable after removing the pin 41.-

lVhen the furnace isin operation with the central shaft assembled with its rabble arms, the path of the cooling fluid is from the interior of the shaft. conduit 44 through the extension outlets 45' into the adaptor conduit portions 42, thence into the rabble arm conduits 28 to the end' of the rabble arms. The cooling fluid is then returned through the annular space 29 in therabble arniand a correspondingannular space 47- Withintlle adaptor member and thence to the annular space inside the centralshaft. lV-ith the constructionas described, the openings 34 and 35, notwithstanding the demountahle construction, maybe made of ample sizeto per mit the fluid to freely flow therethroughand at the-same time'the dimensions of the various parts are kept within practical limits.

Alsmthese constructional features provide the substantially maximum possible interior Wall areaofeach partzdirectly exposed to the circulating cooling fluid and. thus protected from overheating. V

In Figs. 9 and 10 a rabble tooth is illustrated provided with a substantially vertically extending oreengeging area 48 sup ported at its upper: edge uponthe rabble arm by a mortise and tenon joint: construction. The tenon portion as shown in 9 may take the form of flange members 49 and 50 eXte-ndingto either sideofthe plate 48' for engaging a corresponding mortise portion 51, the mortise portion'beingpreferably cast integrally upon the underside of the-rabble arm body ortio-n. Itwillbe noted that each of the rab 10 teeth thus individually and demountably secured to the rabble arm at a fixed posit-ion alongtlie arm and thatfthe mortise and tenon portions extend" in the general directionof travel of the teetlrand are of increasing Width toward the direction of travel, whereby a Wedge-like engagement is obtained. That is, during the operation of the furnace, as the rabble teeth, pass through the materialbeing treated, the teeth Will be either securely held, or if any slight movement takes place by reason of the forces exerted by the ore acting againstthe teeth, such movement Willscrve to bring, the mor tise and tenon portions into afirm wedgi'ng engagement. Referring to Fig. 2, it Will be observed that the rabble teeth nearer the supported end of the rabbie arm are positioned at progressively increasing'anglesin respect to thegenerahdirection of travel of of that member.

the "teeth i whereby proper nibbling: is secured notwithstanding the pomibility of using standardized teothvall alike. :By thus using standardized teeth; manufacturing operationsare greatly simplifiedand in addition, the rabble arm assembly. may: be .more quickly. completed without danger. of mistakes suchzasplacing teeth having certain angles at improper positions;

When two ormore rabblearms are used .lIliCOIlIIQOtlOILWlth a single liearth,.it.is desirable as above stated,-to so position the rabble teeth along. the. arms that the respeetivepathsofi travel oft/he teeth on the several arms will be inter-spaced;v Therefore, eachiof the-arms is to that extent preferably constructed differently. 'On the otherhand,

ibis-desirable for the'reduction of the nun!- ber of necessary spare parts-and the manufacturingcost's, to make all ofthembhle arms interchangeable and! of a standard design. Accordingly, it has: been the prevailing practice heretofore, in. orderto' secure the desired interspacing. ofi-tlle. paths of the rabble teeth, to provide.meanssuch as the longitudinal channel above referred to and in which by suitableaspacer members the teeth may be adjustably mounted'l in the" desired positions.v To eliminate the disadvantages of such an arrangement, according to this. invention each of. the quick-detachablerrabble arms withthe rabbleteeth indiv-idually mounted. thereon may be made substantially alike but adaptonmembers of different lengths and attached: to the furnace shaft 7 by the xsemi-permanenb bolted" joint may be provided for supporting the various arms with the rabble teeth at the desired radial, distances from the central shaft to 7 105.

produce the interspac'ingrefermd to. For

example if two rabble arms are provided for i a single hearth, as visfindicated in Fig.1,

thentw'o' adaptor. members 31 and31 of different'lengths-may be used as indicated in Figs; 3 and 4.- These two adaptor members may: be substantially identical in construction" except. for the lengths thereof and accordingly in the drawings like numerals are used to designate. corresponding parts of these'tyvomembers. v v

' If vdesired,nseveral rabbie teeth may be mounted upon the adaptor member in a manner simila'rto the mountin of the rabble iio teethupon the rabble arm itse f." However,

the adaptor member may beofa substantial I length as compared with the rabble. arm itself, so that the arm and adaptor-together may be described as arsectional mbble arm, which in thisinstm is made up-of; two

, both slightly different sections joined end to end by the inter engaging plug and socket portions. WVith such a sectional rabble arm, it is a simple matter to remove the outer section as a whole together with the rabble teeth mounted there on, whenever it is desired to repair or replace the arm, of any of the teeth. A spare arm of standard design already equipped with a full set of teeth in good condition may be immediately inserted to replace the arm taken out. Thereafter at the operators leisure, the broken or worn out teeth may be readily replaced individually without disturbing the teeth that are in good condition. The tim-e during which the furnace is out of working order is thus substantially minimized and only a single spare arm is necessary in view ofthe standardized construction.

According to this invention, if desired,

the adaptor member may be formed at one end with means of any one of several conventional types for engagement with the fur nace shaft and formed at its other end with socket means of another conventional type for receiving the outer rabble arm section. For example, theinner and outer wall members of the adaptor member may, be formed at the furnace shaft end in a manner corres onding to the plug portion or inner end of tie rabble arm member per so. Also in another example shown 1n F 1g. 11, a rabble arm member 52' is formed with an outer housing member .53 enclosing an internal cooling fluidcondult 54;. vAt 55 and 56 respectively the members 53 and 541- are en- 'struction of' Fig.. 11, a longitudinal slot 59 for the purpose above stated is provided along the length of the rabble arm 52 and is extended to or communicative with a correspondingslot 60 formed along the under side of the adaptor member, so that teeth may be arranged at desired intervals along members. The transverse sectional views of Figs. 12 and '18 illustrate these parts in further detail. The adaptor member 57, it will be noted, is provided with an internal cooling. fluid conduit 61 located along the lower side of the adaptor member in order to properly meet the cooling fluid openings of the furnace shaft, which in this case would be non-concentric;

In Fig. 14; a rabble arm and adaptor construction are shown ina form similar to that of Figs. 11, 12 and 13, but in this instance internal coolingfluid conduit 63 which is substantially concentrically arranged with the outer shell of the adaptor member for proper engagement with afurnace shaft of construction. Integral supporting webs 64 may be provided for properlypositioning the conduit member 63 within the adaptormember. Also, according to this construction, a rabble arm niem ber 65 is provided with an'mternal cooling T respectively are provided with independent tooth receiving slots 69 and 70.

According to Fig. 15, atubular rabble arm member 71 encircles aninternal conduit member 72, themember 71 being received within an adaptor member 73 at. bearing portions 74 and 75. The internal'oonduit member on the other hand extends substantially the full length of. the adaptor member and is received within a bearing portion 76 at the inner end. of the adaptormember. The adaptor member 73 is formed at its inner end for engagement with socket portions on still another form of furnace shaft. internal conduit 72 is communicativewith the inner conduit of the furnaceshaft by reason of the opening 77, whereas the space between the tubular members 71 and 72 is communicative with the outer annular space of the furnace shaft by reason of openings as at 78;

In Fig. 16 a construction somewhat similar to that of Fig. 15 is illustrated. In this construction an adaptor member 7 9 cooperates with a rabble arm member 80, both of said members enclosing an internal cooling fin-id conduit 81. At the outer end of the rabble arm a combined end plug and cooling fluid conduit holder 82 is provided. The conduit 81 is of suchlength as to extend into the furnace shaft into direct communication with the interior conduit thereof, while the adaptor member at a bearing surface 83 one gages the outer wall of the furnaceshaft.

member the conduit 81 is supported by a bearing portion at 85 cast integral, by reason of web portions 86, witlrthe body portion of the adaptor member. It will be observed that the rabble arm members of the construction of Fig. 15 are interchangeable with the corresponding men'ibers of constructions such as shown in Fig. 1G.

IVhile the inventionhas' been described in detail with respect to particular preferred examples which give satisfactory results, it

Fi l

The

will be understood by those skilled in the art,

after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore in the appended claims to cover all such changes and modifications.

lVhat is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A rabble arm comprising a plurality of sections each having individually demountable rabble teeth mounted in fixed position along the sections, and quick-detachable connecting means for the sections.

2. A roasting furnace rabble arinhaving rabble teeth individually mounted in fixed position along the arm, and interchangeable supporting means for said arm whereby a.

predetermined radius of movement of the teeth is obtainable.

3. In a roasting furnace a plurality of rabble arms supported from a rotating shaft for operating in connection with a single hearth, said arms each having rabble teeth individually mounted in fixed position along the arm, said arms being substantially of like construction as regards the position and spacing thereon of rabble teeth, and adaptor members of different lengths for mounting said arms upon said shaft whereby the respective paths of travel of the teeth on the several arms will be interspaced.

4. In a roasting furnace a plurality of rabble arms supported from a rotating shaft for operating in connection with a single hearth, said arms being substantially of like construction as regards the position and spacing thereon of rabble teeth, and adaptor members of different lengths for mounting said arms upon said shaft whereby the respective paths of travel of the teeth on the several arms will be interspaced.

5. A roastingifurnace rabble arm having teeth at various different desired angles.

7. In combination a rabble arm member having its supporting end formed with means for quick-detachable engagement with a supporting socket, and an adaptor for mounting said arm upon a furnace shaft, said arm member, said adaptor and said shaft having communicating cavities for .conducting cooling fluid therethrough.

8. A roasting furnace rabble arm construction comprising an arm section carrying numerous detachable rabble teeth, and an adaptor member formed with means of a conventional type for engagement with a supporting shaft and formed with socket means of another conventional type for receiving said arm section.

9. A roasting furnace rabble arm construction comprising an air cooled arm section carrying numerous detachable rabble teeth, and an adaptor member formed with means for semi-permanent engagement with a supporting shaft and with means for quick-detachable engagement with said arm section. V 1,

10. A roasting furnace rabble arm construction comprising an arm section formed with a? male portion at its supported end,

and an adaptor portion formed at one end with provision for bolting to a supporting shaft and at its other end with a female portion for receiving said male portion.

11. A roasting furnace rabble arm comprising a plurality of separable armsecti'ons jointed end to end by interengaging plug and socket portions, provision being made within each section and through said interengaging portions for conducting cooling fluid to and from the outer end of the arm.

12A roasting furnace rabble arm comprising a plurality of separable arm sections jointed end to end by interengaging plug and socket portions, one of said sections carrying another of said sections at its outer end.

13. A sectional rabble arm comprising a section supported by a rotatable shaft and carrying another section at its outer end, each section of which comprises an inner conduit for cooling fluid surrounded by an outer supporting conduit.

In testimony whereof I have signed my name to this specification.

.. EDWARD J. FOWLER. 

